controuver

Controuver is a rare, dated literary verb meaning to fabricate a falsehood — typically a malicious lie meant to harm someone's reputation. It survives today mostly through its adjective controuvé (fabricated, trumped-up, as in accusations controuvées), which is far more common than the verb itself.

• On l'accusait d'avoir controuvé cette histoire pour lui nuire. — He was accused of having fabricated this story to harm him.
• Ces rumeurs controuvées ont circulé pendant des mois. — These fabricated rumors circulated for months.
• Il est aisé de controuver un mensonge, plus difficile de le faire croire. — It's easy to fabricate a lie, harder to make it believed.

Modern French almost always uses the adjective controuvé(e) (a claim proven false, une accusation controuvée) rather than conjugating the verb itself — a learner is far more likely to meet this word in its adjectival form than as a finite verb.